Edward "Ed" Dillinger, Sr. is the tertiary and main human antagonist in TRON, and wrote both Sark and the Master Control Program. He was a programmer when he started his job at ENCOM, but soon climbed the ranks until he reached Senior Executive, thanks to the abilities of MCP.

Little did everyone at ENCOM know that Dillinger wrote the MCP to appropriate any program that was considered useful. One of these programs was the game "Space Paranoids" which was actually created by former employee Kevin Flynn. He later used the MCP to keep Flynn from hacking in to find the evidence of the theft.

Eventually however Dillinger began to fear his own creation when the MCP intended to hack into the Pentagon and the Kremlin, threatening to expose Dillinger's theft of Flynn's video games unless he cooperated.

After the termination of the MCP by Tron and Flynn, Dillinger was presumably exposed as a fraud and was sent to prison, which coincides with the scenario the MCP presented to Dillinger in the film.

Flynn describes Dillinger as "not so bright [as himself] but very, very sneaky" due to his success at stealing Flynn's video game designs. Dillinger did however demonstrate more than enough programming skill to convert the MCP from a simple chess program into the corporate raiding tool that facilitated his rise to power. He also clearly possessed enough skill and business acumen to raise ENCOM from its humble beginnings in a garage to the corporate giant it was at the beginning of the movie.

It is suggested that either Flynn or Dillinger is the CEO of fCon in the game TRON 2.0. Dillinger is more likely the true CEO, given the similarity of the names. Plus the voice heard had more of a British accent and the CEO's tactics had a decidedly ruthless methodology to them. Dillinger probably wouldn't have faced more than 5 years of jail time with a good lawyer, and that would have given him plenty of time to found fCon and develop it into a powerful corporation strong enough to be a contender to ENCOM. If indeed he is the true CEO, that is.

Also in Tron: Legacy, the Blu-ray easter egg has a computer chat session with Dillinger Jr. conversing with someone behind the name of MCNTRL. This could mean that this is Dillinger, Sr. (because Jr. calls MCNTRL Dad) or the MCP is set to return in Tron 3, which will tentatively begin production in 2014.